/**
 * $RCSfile: Properties.java,v $
 * $Revision: 1.1 $
 * $Date: 2014/07/08 00:25:45 $
 *
 * Copyright (C) 2003 spk, Inc. All rights reserved.
 *
 * This software is the proprietary information of spk, Inc.
 * Use is subject to license terms.
 */
package com.ds.common.property;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.util.Date;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 *  The <code>Properties</code> class represents a persistent set of properties.
 *  The <code>Properties</code> can be saved to a stream or loaded from a
 *  stream. Each key and its corresponding value in the property list is a
 *  string. <p>
 *
 *  A property list can contain another property list as its "defaults"; this
 *  second property list is searched if the property key is not found in the
 *  original property list. <p>
 *
 *  Because <code>Properties</code> inherits from <code>Hashtable</code>, the
 *  <code>put</code> and <code>putAll</code> methods can be applied to a <code>Properties</code>
 *  object. Their use is strongly discouraged as they allow the caller to insert
 *  entries whose keys or values are not <code>Strings</code>. The <code>setProperty</code>
 *  method should be used instead. If the <code>store</code> or <code>save</code>
 *  method is called on a "compromised" <code>Properties</code> object that
 *  contains a non-<code>String</code> key or value, the call will fail. <p>
 *
 *  <a name="encoding"></a> When saving properties to a stream or loading them
 *  from a stream, the ISO 8859-1 character encoding is used. For characters
 *  that cannot be directly represented in this encoding, <a
 *  href="http://java.sun.com/docs/books/jls/html/3.doc.html#100850">Unicode
 *  escapes</a> are used; however, only a single 'u' character is allowed in an
 *  escape sequence. The native2ascii tool can be used to convert property files
 *  to and from other character encodings.
 *
 *@author     Arthur van Hoff
 *@author     Michael McCloskey
 *@see        <a href="../../../tooldocs/solaris/native2ascii.html">native2ascii
 *      tool for Solaris</a>
 *@see        <a href="../../../tooldocs/windows/native2ascii.html">native2ascii
 *      tool for Windows</a>
 *@version    1.64, 06/26/00
 *@since      JDK1.0
 */
public class Properties extends Hashtable {
    /**
     *  use serialVersionUID from JDK 1.1.X for interoperability
     */
    private final static long serialVersionUID = 4112578634029874840L;

    /**
     *  A property list that contains default values for any keys not found in
     *  this property list.
     *
     *@serial
     */
    protected Properties defaults;

    /**
     *  Creates an empty property list with no default values.
     */
    public Properties() {
        this(null);
    }

    /**
     *  Creates an empty property list with the specified defaults.
     *
     *@param  defaults  the defaults.
     */
    public Properties(Properties defaults) {
        this.defaults = defaults;
    }

    /**
     *  Calls the <tt>Hashtable</tt> method <code>put</code>. Provided for
     *  parallelism with the <tt>getProperty</tt> method. Enforces use of strings
     *  for property keys and values. The value returned is the result of the <tt>
     *  Hashtable</tt> call to <code>put</code>.
     *
     *@param  key    the key to be placed into this property list.
     *@param  value  the value corresponding to <tt>key</tt> .
     *@return        the previous value of the specified key in this property
     *      list, or <code>null</code> if it did not have one.
     *@see           #getProperty
     *@since         1.2
     */
    public synchronized Object setProperty(String key, String value) {
        return put(key, value);
    }

    private final static String keyValueSeparators = "=: \t\r\n\f";

    private final static String strictKeyValueSeparators = "=:";

    private final static String specialSaveChars = "=: \t\r\n\f#!";

    private final static String whiteSpaceChars = " \t\r\n\f";

    /**
     *  Reads a property list (key and element pairs) from the input stream. The
     *  stream is assumed to be using the ISO 8859-1 character encoding. <p>
     *
     *  Every property occupies one line of the input stream. Each line is
     *  terminated by a line terminator (<code>\n</code> or <code>\r</code> or
     *  <code>\r\n</code>). Lines from the input stream are processed until end of
     *  file is reached on the input stream. <p>
     *
     *  A line that contains only whitespace or whose first non-whitespace
     *  character is an ASCII <code>#</code> or <code>!</code> is ignored (thus,
     *  <code>#</code> or <code>!</code> indicate comment lines). <p>
     *
     *  Every line other than a blank line or a comment line describes one
     *  property to be added to the table (except that if a line ends with \, then
     *  the following line, if it exists, is treated as a continuation line, as
     *  described below). The key consists of all the characters in the line
     *  starting with the first non-whitespace character and up to, but not
     *  including, the first ASCII <code>=</code>, <code>:</code>, or whitespace
     *  character. All of the key termination characters may be included in the
     *  key by preceding them with a \. Any whitespace after the key is skipped;
     *  if the first non-whitespace character after the key is <code>=</code> or
     *  <code>:</code>, then it is ignored and any whitespace characters after it
     *  are also skipped. All remaining characters on the line become part of the
     *  associated element string. Within the element string, the ASCII escape
     *  sequences <code>\t</code>, <code>\n</code>, <code>\r</code>, <code>\\</code>
     *  , <code>\"</code>, <code>\'</code>, <code>\ &#32;</code> &#32;(a backslash
     *  and a space), and <code>&#92;u</code><i>xxxx</i> are recognized and
     *  converted to single characters. Moreover, if the last character on the
     *  line is <code>\</code>, then the next line is treated as a continuation of
     *  the current line; the <code>\</code> and line terminator are simply
     *  discarded, and any leading whitespace characters on the continuation line
     *  are also discarded and are not part of the element string. <p>
     *
     *  As an example, each of the following four lines specifies the key <code>"Truth"</code>
     *  and the associated element value <code>"Beauty"</code>: <p>
     *
     *  <pre>
     * Truth = Beauty
     *	Truth:Beauty
     * Truth			:Beauty
     * </pre> As another example, the following three lines specify a single
     *  property: <p>
     *
     *  <pre>
     * fruits				apple, banana, pear, \
     *                                  cantaloupe, watermelon, \
     *                                  kiwi, mango
     * </pre> The key is <code>"fruits"</code> and the associated element is: <p>
     *
     *  <pre>"apple, banana, pear, cantaloupe, watermelon, kiwi, mango"</pre> Note
     *  that a space appears before each <code>\</code> so that a space will
     *  appear after each comma in the final result; the <code>\</code>, line
     *  terminator, and leading whitespace on the continuation line are merely
     *  discarded and are <i>not</i> replaced by one or more other characters. <p>
     *
     *  As a third example, the line: <p>
     *
     *  <pre>cheeses
     * </pre> specifies that the key is <code>"cheeses"</code> and the associated
     *  element is the empty string.<p>
     *
     *
     *
     *@param  inStream         the input stream.
     *@exception  IOException  if an error occurred when reading from the input
     *      stream.
     */
    public synchronized void load(InputStream inStream) throws IOException {

        BufferedReader in = new BufferedReader(new InputStreamReader(inStream, "GBK"));
        while (true) {
            // Get next line
            String line = in.readLine();
            if (line == null) {
                return;
            }

            if (line.length() > 0) {
                // Continue lines that end in slashes if they are not comments
                char firstChar = line.charAt(0);
                if ((firstChar != '#') && (firstChar != '!')) {
                    while (continueLine(line)) {
                        String nextLine = in.readLine();
                        if (nextLine == null) {
                            nextLine = "";
                        }
                        String loppedLine = line.substring(0, line.length() - 1);
                        // Advance beyond whitespace on new line
                        int startIndex = 0;
                        for (startIndex = 0; startIndex < nextLine.length(); startIndex++) {
                            if (whiteSpaceChars.indexOf(nextLine.charAt(startIndex)) == -1) {
                                break;
                            }
                        }
                        nextLine = nextLine.substring(startIndex, nextLine.length());
                        line = new String(loppedLine + nextLine);
                    }

                    // Find start of key
                    int len = line.length();
                    int keyStart;
                    for (keyStart = 0; keyStart < len; keyStart++) {
                        if (whiteSpaceChars.indexOf(line.charAt(keyStart)) == -1) {
                            break;
                        }
                    }

                    // Blank lines are ignored
                    if (keyStart == len) {
                        continue;
                    }

                    // Find separation between key and value
                    int separatorIndex;
                    for (separatorIndex = keyStart; separatorIndex < len; separatorIndex++) {
                        char currentChar = line.charAt(separatorIndex);
                        if (currentChar == '\\') {
                            separatorIndex++;
                        }
                        else if (keyValueSeparators.indexOf(currentChar) != -1) {
                            break;
                        }
                    }

                    // Skip over whitespace after key if any
                    int valueIndex;
                    for (valueIndex = separatorIndex; valueIndex < len; valueIndex++) {
                        if (whiteSpaceChars.indexOf(line.charAt(valueIndex)) == -1) {
                            break;
                        }
                    }

                    // Skip over one non whitespace key value separators if any
                    if (valueIndex < len) {
                        if (strictKeyValueSeparators.indexOf(line.charAt(valueIndex)) != -1) {
                            valueIndex++;
                        }
                    }

                    // Skip over white space after other separators if any
                    while (valueIndex < len) {
                        if (whiteSpaceChars.indexOf(line.charAt(valueIndex)) == -1) {
                            break;
                        }
                        valueIndex++;
                    }
                    String key = line.substring(keyStart, separatorIndex);
                    String value = (separatorIndex < len) ? line.substring(valueIndex, len) : "";

                    // Convert then store key and value
                    key = loadConvert(key);
                    value = loadConvert(value);
                    put(key, value);
                }
            }
        }
    }

    /*
     *  Returns true if the given line is a line that must
     *  be appended to the next line
     */
    /**
     *  Description of the Method
     *
     *@param  line  Description of the Parameter
     *@return       Description of the Return Value
     */
    private boolean continueLine(String line) {
        int slashCount = 0;
        int index = line.length() - 1;
        while ((index >= 0) && (line.charAt(index--) == '\\')) {
            slashCount++;
        }
        return (slashCount % 2 == 1);
    }

    /*
     *  Converts encoded &#92;uxxxx to unicode chars
     *  and changes special saved chars to their original forms
     */
    /**
     *  Description of the Method
     *
     *@param  theString  Description of the Parameter
     *@return            Description of the Return Value
     */
    private String loadConvert(String theString) {
        char aChar;
        int len = theString.length();
        StringBuffer outBuffer = new StringBuffer(len);

        for (int x = 0; x < len;) {
            aChar = theString.charAt(x++);
            if (aChar == '\\') {
                aChar = theString.charAt(x++);
                if (aChar == 'u') {
                    // Read the xxxx
                    int value = 0;
                    for (int i = 0; i < 4; i++) {
                        aChar = theString.charAt(x++);
                        switch (aChar) {
                            case '0' :
                            case '1' :
                            case '2' :
                            case '3' :
                            case '4' :
                            case '5' :
                            case '6' :
                            case '7' :
                            case '8' :
                            case '9' :
                                value = (value << 4) + aChar - '0';
                                break;
                            case 'a' :
                            case 'b' :
                            case 'c' :
                            case 'd' :
                            case 'e' :
                            case 'f' :
                                value = (value << 4) + 10 + aChar - 'a';
                                break;
                            case 'A' :
                            case 'B' :
                            case 'C' :
                            case 'D' :
                            case 'E' :
                            case 'F' :
                                value = (value << 4) + 10 + aChar - 'A';
                                break;
                            default :
                                throw new IllegalArgumentException("Malformed \\uxxxx encoding.");
                        }
                    }
                    outBuffer.append((char)value);
                }
                else {
                    if (aChar == 't') {
                        aChar = '\t';
                    }
                    else if (aChar == 'r') {
                        aChar = '\r';
                    }
                    else if (aChar == 'n') {
                        aChar = '\n';
                    }
                    else if (aChar == 'f') {
                        aChar = '\f';
                    }
                    outBuffer.append(aChar);
                }
            }
            else {
                outBuffer.append(aChar);
            }
        }
        return outBuffer.toString();
    }

    /*
     *  Converts unicodes to encoded &#92;uxxxx
     *  and writes out any of the characters in specialSaveChars
     *  with a preceding slash
     */
    /**
     *  Description of the Method
     *
     *@param  theString    Description of the Parameter
     *@param  escapeSpace  Description of the Parameter
     *@return              Description of the Return Value
     */
    private String saveConvert(String theString, boolean escapeSpace) {
        int len = theString.length();
        StringBuffer outBuffer = new StringBuffer(len * 2);

        for (int x = 0; x < len; x++) {
            char aChar = theString.charAt(x);
            switch (aChar) {
                case ' ' :
                    if (x == 0 || escapeSpace) {
                        outBuffer.append('\\');
                    }

                    outBuffer.append(' ');
                    break;
                case '\\' :
                    outBuffer.append('\\');
                    outBuffer.append('\\');
                    break;
                case '\t' :
                    outBuffer.append('\\');
                    outBuffer.append('t');
                    break;
                case '\n' :
                    outBuffer.append('\\');
                    outBuffer.append('n');
                    break;
                case '\r' :
                    outBuffer.append('\\');
                    outBuffer.append('r');
                    break;
                case '\f' :
                    outBuffer.append('\\');
                    outBuffer.append('f');
                    break;
                default :
                    if ((aChar < 0x0020) || (aChar > 0x007e)) {
                        outBuffer.append('\\');
                        outBuffer.append('u');
                        outBuffer.append(toHex((aChar >> 12) & 0xF));
                        outBuffer.append(toHex((aChar >> 8) & 0xF));
                        outBuffer.append(toHex((aChar >> 4) & 0xF));
                        outBuffer.append(toHex(aChar & 0xF));
                    }
                    else {
                        if (specialSaveChars.indexOf(aChar) != -1) {
                            outBuffer.append('\\');
                        }
                        outBuffer.append(aChar);
                    }
            }
        }
        return outBuffer.toString();
    }

    /**
     *  Calls the <code>store(OutputStream out, String header)</code> method and
     *  suppresses IOExceptions that were thrown.
     *
     *@param  out     an output stream.
     *@param  header  a description of the property list.
     *@deprecated     This method does not throw an IOException if an I/O error
     *      occurs while saving the property list. As of the Java 2 platform v1.2,
     *      the preferred way to save a properties list is via the <code>store(OutputStream out,
     * String header)</code> method.
     */
    public synchronized void save(OutputStream out, String header) {
        try {
            store(out, header);
        }
        catch (IOException e) {}
    }

    /**
     *  Writes this property list (key and element pairs) in this <code>Properties</code>
     *  table to the output stream in a format suitable for loading into a <code>Properties</code>
     *  table using the <code>load</code> method. The stream is written using the
     *  ISO 8859-1 character encoding. <p>
     *
     *  Properties from the defaults table of this <code>Properties</code> table
     *  (if any) are <i>not</i> written out by this method. <p>
     *
     *  If the header argument is not null, then an ASCII <code>#</code>
     *  character, the header string, and a line separator are first written to
     *  the output stream. Thus, the <code>header</code> can serve as an
     *  identifying comment. <p>
     *
     *  Next, a comment line is always written, consisting of an ASCII <code>#</code>
     *  character, the current date and time (as if produced by the <code>toString</code>
     *  method of <code>Date</code> for the current time), and a line separator as
     *  generated by the Writer. <p>
     *
     *  Then every entry in this <code>Properties</code> table is written out, one
     *  per line. For each entry the key string is written, then an ASCII <code>=</code>
     *  , then the associated element string. Each character of the element string
     *  is examined to see whether it should be rendered as an escape sequence.
     *  The ASCII characters <code>\</code>, buttonviews, newline, and carriage return are
     *  written as <code>\\</code>, <code>\t</code>, <code>\n</code>, and <code>\r</code>
     *  , respectively. Characters less than <code>&#92;u0020</code> and
     *  characters greater than <code>&#92;u007E</code> are written as <code>&#92;u</code>
     *  <i>xxxx</i> for the appropriate hexadecimal value <i>xxxx</i> . Leading
     *  space characters, but not embedded or trailing space characters, are
     *  written with a preceding <code>\</code>. The key and value characters
     *  <code>#</code>, <code>!</code> , <code>=</code>, and <code>:</code> are
     *  written with a preceding slash to ensure that they are properly loaded.
     *  <p>
     *
     *  After the entries have been written, the output stream is flushed. The
     *  output stream remains open after this method returns.
     *
     *@param  out              an output stream.
     *@param  header           a description of the property list.
     *@exception  IOException  if writing this property list to the specified
     *      output stream throws an <tt>IOException</tt> .
     *@since                   1.2
     */
    public synchronized void store(OutputStream out, String header) throws IOException {
        BufferedWriter awriter;
        awriter = new BufferedWriter(new OutputStreamWriter(out));
        if (header != null) {
            writeln(awriter, "#" + header);
        }
        writeln(awriter, "#" + new Date().toString());
        for (Enumeration e = keys(); e.hasMoreElements();) {
            String key = (String)e.nextElement();
            String val = (String)get(key);
            key = saveConvert(key, true);

            /*
             *  No need to escape embedded and trailing spaces for value, hence
             *  pass false to flag.
             */
            val = saveConvert(val, false);
            writeln(awriter, key + "=" + val);
        }
        awriter.flush();
    }

    /**
     *  Description of the Method
     *
     *@param  bw               Description of the Parameter
     *@param  s                Description of the Parameter
     *@exception  IOException  Description of the Exception
     */
    private static void writeln(BufferedWriter bw, String s) throws IOException {
        bw.write(s);
        bw.newLine();
    }

    /**
     *  Searches for the property with the specified key in this property list. If
     *  the key is not found in this property list, the default property list, and
     *  its defaults, recursively, are then checked. The method returns <code>null</code>
     *  if the property is not found.
     *
     *@param  key  the property key.
     *@return      the value in this property list with the specified key value.
     *@see         #setProperty
     *@see         #defaults
     */
    public String getProperty(String key) {
        Object oval = super.get(key);
        String sval = (oval instanceof String) ? (String)oval : null;
        return ((sval == null) && (defaults != null)) ? defaults.getProperty(key) : sval;
    }

    /**
     *  Searches for the property with the specified key in this property list. If
     *  the key is not found in this property list, the default property list, and
     *  its defaults, recursively, are then checked. The method returns the
     *  default value argument if the property is not found.
     *
     *@param  key           the hashtable key.
     *@param  defaultValue  a default value.
     *@return               the value in this property list with the specified key
     *      value.
     *@see                  #setProperty
     *@see                  #defaults
     */
    public String getProperty(String key, String defaultValue) {
        String val = getProperty(key);
        return (val == null) ? defaultValue : val;
    }

    /**
     *  Returns an enumeration of all the keys in this property list, including
     *  distinct keys in the default property list if a key of the same name has
     *  not already been found from the main properties list.
     *
     *@return    an enumeration of all the keys in this property list, including
     *      the keys in the default property list.
     *@see       Enumeration
     *@see       java.util.Properties#defaults
     */
    public Enumeration propertyNames() {
        Hashtable h = new Hashtable();
        enumerate(h);
        return h.keys();
    }

    /**
     *  Prints this property list out to the specified output stream. This method
     *  is useful for debugging.
     *
     *@param  out  an output stream.
     */
    public void list(PrintStream out) {
        out.println("-- listing properties --");
        Hashtable h = new Hashtable();
        enumerate(h);
        for (Enumeration e = h.keys(); e.hasMoreElements();) {
            String key = (String)e.nextElement();
            String val = (String)h.get(key);
            if (val.length() > 40) {
                val = val.substring(0, 37) + "...";
            }
            out.println(key + "=" + val);
        }
    }

    /**
     *  Prints this property list out to the specified output stream. This method
     *  is useful for debugging.
     *
     *@param  out  an output stream.
     *@since       JDK1.1
     */
    /*
     *  Rather than use an anonymous inner class to share common code, this
     *  method is duplicated in order to ensure that a non-1.1 compiler can
     *  compile this file.
     */
    public void list(PrintWriter out) {
        out.println("-- listing properties --");
        Hashtable h = new Hashtable();
        enumerate(h);
        for (Enumeration e = h.keys(); e.hasMoreElements();) {
            String key = (String)e.nextElement();
            String val = (String)h.get(key);
            if (val.length() > 40) {
                val = val.substring(0, 37) + "...";
            }
            out.println(key + "=" + val);
        }
    }

    /**
     *  Enumerates all key/value pairs in the specified hastable.
     *
     *@param  h  the hashtable
     */
    private synchronized void enumerate(Hashtable h) {
        if (defaults != null) {
            defaults.enumerate(h);
        }
        for (Enumeration e = keys(); e.hasMoreElements();) {
            String key = (String)e.nextElement();
            h.put(key, get(key));
        }
    }

    /**
     *  Convert a nibble to a hex character
     *
     *@param  nibble  the nibble to convert.
     *@return         Description of the Return Value
     */
    private static char toHex(int nibble) {
        return hexDigit[(nibble & 0xF)];
    }

    /**
     *  A table of hex digits
     */
    private final static char[] hexDigit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
}
